I have several bathrooms in my house.
An up stairs with toilet and sink. About 20% use
A main floor tub/shower, sink and toilet about 70% of all bathroom use is with this.
A downstairs rec room toilet, sink, and shower (no tub) about 10% use.
I have a functioning urinal in my garage but it’s so rarely used I’ll set it at 0%.
I’ve done enough experimenting to be able to say with confidence that using the facilities in any part of the house does not affect any other, EXCEPT:
When the shower is on in the main floor and the downstairs toilet is flushed, the main floor shower starts blasting cold water.
When the main floor tub is on this doesn’t happen.
Why would this only happen with the shower?
And Why cold water? My downstairs toilet is not connected to the hot water pipes.
Luckily my downstairs bathroom is not used enough for this to be a pressing issue except on my inquisitive mind. So…? WTF?